A Triple-Band Passive Detector Circuit With Improved Sensitivity

This work presents a triple-band passive detector circuit for monitoring radiated power by the base stations at 3G, and 4G/LTE bands. The detector does not use any active component other than one single Schottky diode. A miniaturized triple-band impedance matching network is designed. This design can detect three frequencies simultaneously. A new design strategy for the input matching network helps to decrease the overall size of the detector to just 29.4 mm × 10.43 mm when fabricated in a RO4003C substrate with dielectric constant 3.55. Improved matching also helps to greatly enhance the sensitivity of the detector circuit at the desired frequency points. Measurement results show that it can detect an RF input power as low as -45 dBm without using any RF or low frequency amplifier. Compared to the previous designs, this detector has simpler impedance matching network, compactness and better response at low input powers.